[IAUC] IAUC 9245: C/2011 W3 [25139-2012/04-R1]

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                                                  Circular No. 9245
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
New postal address:  Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
CBATIAU en EPS.HARVARD.EDU           ISSN 0081-0304
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Prepared using the Tamkin Foundation Computer Network


COMET C/2011 W3 (LOVEJOY)
     As first announced on CBET 2930, Terry Lovejoy, Thornlands,
Qld., Australia, reported his discovery of a comet on three CCD
images obtained each on Nov. 27.7 and 29.7 UT with a Celestron
0.20-m f/2.1 Schmidt-Cassegrain reflector (+ QHY9 camera) in the
course of his normal comet-search program; the comet appeared then
as a clearly diffuse circular object approximately 1' in diameter,
with a central condensation of mag 16 and no apparent tail.  Clouds
affected his observations on Nov. 29, and the astrometry was
severely affected by a crowded star field (Lovejoy estimating
uncertainty as much as +/- 15" or more).  By Dec. 1.7, Lovejoy
found that the comet had brightened by perhaps a magnitude and was
now well-condensed with a 1'.2 coma.  Astrometric measurements of
his CCD frames (those on Nov. 27 and 29 by Lovejoy, those on Dec. 1
by G. V. Williams) are given below:

     2011 UT             R.A. (2000) Decl.       Mag.   Observer
     Nov. 27.73470   12 47 38.8    -51 39 29     13     Lovejoy
          27.74030   12 47 45.6    -51 39 33              "
          27.74650   12 47 51.8    -51 39 50              "
          29.72801   13 27 30.5    -52 18 25     13       "
          29.72861   13 27 30.5    -52 18 24              "
          29.72907   13 27 31.2    -52 18 27              "
          29.72953   13 27 31.8    -52 18 30              "
     Dec.  1.73183   14 09 33.9    -52 00 41     12       "
           1.73229   14 09 34.4    -52 00 44              "
           1.73274   14 09 34.7    -52 00 44              "

     Additional physical observations:  Dec. 1.6 UT, well-condensed,
circular coma of diameter approximately 1' and a nuclear
condensation of mag 16.6-17.3 (A. C. Gilmore and P. M. Kilmartin,
Mount John 1.0-m reflector); Dec. 2.3, 14" round coma with a very
broad 51".3 tail extending predominately in p.a. 327 deg (R. Holmes,
T. Linder, and V. Hoette with a 0.41-m reflector at Cerro Tololo);
Dec. 2.7, quite diffuse with a coma diameter of 2', total mag 11.0
in an aperture of radius 61", elongated toward p.a. 45 deg (H. Sato,
Tokyo; V-band images obtained remotely with a 0.32-m reflector at
the GRAS Observatory located near Officer, Vic., Australia); Dec.
2.75, diffuse coma of diameter about 13" with very little central
condensation (T. Lister, remotely with the 2.0-m "Faulkes Telescope
South" at Siding Spring); Dec. 6.7, strongly condensed with a 100"
coma of total mag 10.3 in a circular aperture of radius 51" (Sato);
Dec. 7.7, moderately condensed 1' coma of total mag 9.4 in aperture
radius 29" (S. Kiyota and Sato).

                      (C) Copyright 2011 CBAT
2011 December 18               (9245)            Daniel W. E. Green